Arene borylation through C-H activation using Cu3(BTC)2 as heterogeneous catalyst

C-H borylation by diborane is an important process to access organoboron compounds. Noble metals, including Ir and Rh-based complexes either in the form of homogeneous or heterogeneous catalysts, have been reported to promote arene C-H borylation. Recently, metal organic frameworks (MOFs) having Ir and Co as active sites have been used as catalysts, but they require co-catalysts. In the present study, commercially available Cu-3(BTC)(2) (BTC: 1,3,5-benzenetricarboxylate) MOF is reported as an effective catalyst to promote borylation of arenes through C-H activation employing bis(pinacolato)diboron (1) as reagent leading to benzylic and aromatic borylation products. Interestingly, other related MOFs like MIL-101(Cr) and Al(OH)(BDC) (BDC: 1,4-benzenedicarboxylate) do not exhibit catalytic activity under identical conditions. Mechanistic studies using in-situ IR spectroscopy reveal that Cu ions play a crucial role in activating the arene and B-B bond in 1.

Automated summary

In this study, Cu-3(BTC)(BTC: 1,3,5-benzenetricarboxylate) MOF is reported to be an effective catalyst for promoting the borylation of arenes through C-H activation. Compared to other MOFs, Cu-3(BTC) shows higher catalytic activity, with copper ions playing a crucial role in the catalytic mechanism.